Semiconductor devices are fabricated by stacking thin films repeatedly in order to form a predetermined circuit pattern on a semiconductor wafer, and a plurality of unit processes are repeatedly performed such as deposition, photolithography, etching, and so on in order to form and laminate thin films.
A photolithography process among unit processes is a process of forming patterns on a wafer, and includes steps of photoresist coating, exposure, and developing. By using patterns formed on a wafer through developing process, and etching the uppermost layer of the wafer, devices having a predetermined patterns are formed.
A coater is used in the photoresist coating in which light-sensitive material, photoresist is uniformly applied on the surface of a wafer by using the coater. In the step of exposure, a stepper is used to make light pass through the circuit patterns of the mask so as to exposure the circuit patterns on the exposure subject (film, wafer, etc.) having photoresist layer thereon. In the developing process, a developer is used to develop the portions on the surface of the wafer which received light in the exposure process.
Here, for the exposure system to perform the exposure process as prior art of technology, it is recommended Korean Patent Registration No. 1379379, titled ‘Wafer Chuck Balancing Apparatus for Stepper’.
All exposure systems including the exposure apparatus in the prior art of technology are structured such that a light source of the exposure module fixedly installed at a position emit light to across the entire surface of the exposure subject located on an exposure stage.
However, since the exposure module is fixedly installed at a position, the size of an exposure subject to be exposed is limited according to the product specifications of an exposure module, and it is impossible to perform exposure by one time on the exposure subject being greater in length than the size reference of the exposure module. Therefore, the availability of the exposure systems is decreased, and the size of the exposure module needs to excessively enlarge in order to perform exposure a long-sized exposure subject by one time.
Therefore, it is highly demanded to produce an exposure system having the function to enable expose an exposure subject more efficiently regardless of the size of the exposure subject.